Embodiments of the present invention relate to an array substrate and a manufacturing method thereof.
Currently, thin film transistors liquid crystal displays (TFT-LCDs) have advantages of excellent display quality, low manufacturing cost, low power consumption, no radiation and the like, and thus have predominated in the current flat plate display market. With developments of manufacture technologies, display quality of TFT-LCDs is gradually improved.
A TFT-LCD generally comprises a liquid crystal panel, a drive circuit and a backlight. The liquid crystal panel is the most important component in the TFT-LCD, and the liquid crystal panel is formed by injecting liquid crystal into the space between two glass substrates, then sealing a periphery of the substrates by using sealant, and attaching respectively two polarizer plates, whose polarization directions are perpendicular to each other, to the two glass substrates. Herein, the upper glass substrate is a color filter substrate, and a lower glass substrate is a TFT array substrate. A plurality of thin film transistors in a matrix arrangement and some peripheral circuits are manufactured on the TFT array substrate.
Generally, a black matrix is formed on the color filter substrate, and the material for the black matrix may be a non-transparent metal film, such as Cr film, and the metal film can reflect light. When light generated by the backlight transmits through the TFT array, a portion of the light is incident on the nontransparent metal film, and that portion of the light is reflected and mostly radiated on the semiconductor layer positioned at the channel of the TFT. The semiconductor layer is formed of a photosensitive material, and when being radiated by light, may give rise to dark current, and the dark current can increase the turning-off current of the TFT, thus reducing the retaining time of pixel charges, affecting a gray level change of the TFT-LCD, and an image flickering may occur in some situations.